The problem with caps is that there are some that cannot make the EXP to get to the world, resulting in them being stuck. It happened to a Beta friend of mine before Celestia came out; she was stuck at level 49 for around a year.

If you don't like others teleporting to you, utilize the option to not allow friends to teleport. This way, they must ask before teleporting. You can turn the option on and off easily.